In various functional conditions involving peripheral vasoconstriction a more or less widespread change toward acidity takes place within certain tissues. The change is frequently independent of any in the blood. Indeed the blood can become more alkaline while the tissue acidosis is developing.
When the blood volume is diminished abruptly but not too greatly, by hemorrhage or by anhydremia, the acidosis which develops in the superficial connective tissue and in the skeletal muscles is patchy in distribution, being limited to areas of local ischemia themselves the result of a compensatory vasoconstriction which affects certain regions only. There is a second type of patchy ischemia (and of acidosis) which occurs under circumstances of moderate depletion and is referable to local pressure differences that are so slight as to be ineffective under normal circumstances. A generalized acidosis throughout the superficial tissue develops when depletion is extreme. All these are outlying acidoses, since they lie without the influence of the blood. In the viscera no such acidoses have been found.